Install the cement backer board first with a factory edge at the outside corner.
How to tile a wall outside corner.
2 install the tiles on the.
Cut the final piece of tile on a wet saw to fit the wall so that its edge is flush with the corner.
Then install the drywall with j trim on the outside edge so it runs past the cement board the thickness of the tile.
I do not recommend finishing any tile edge with caulking.
If you re creating a tiled pony wall like justina blakeney s mitering might be a good option for you.
You can choose to miter the edges of your tile too.
Stop each course when a full tile won t fit in the corner by the adjacent wall.
Start installing the wall tiles from the corner as in the image.
Use a notched trowel to spread tile adhesive on one side of the corner.
Mitering is where a joint is created by two pieces of tile at a 90 angle to create a corner.
Make sure the corner is framed square.
Next spread tile adhesive on the wall corner and secure the plastic corner trim making sure it is perfectly plumb.
Use a large spirit level to see if the corner is plumb from top to bottom.
Hold the trowel at 45ยบ to make sure the ridges are large enough to glue the tiles.
Set the tiles in thinset mortar spread with a notched trowel putting spacers between them.
She also used glazed edges in this project in her tiled niches.
This do it yourself video how to install tile edge trims on a shower outside corners shows how to install tile edge trim on a wall and curb outside corne.
If you cant find a suitable corner round you could finish the edge of the tile at the front of the curb or finish the front edge corner if you choose to tile the front side of the curb which i recommend with grout.
Hang all the full tiles over both walls leading to the corner starting each wall at the middle of the bottom and building up and out course by course.